• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.776-782
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• 2015

$TiO_2-SnO_2$ nanoparticles with an average diameter of 3~5 nm were synthesized by hydrolysis of titanium tetraisopropoxide (TTIP) and tin chloride to depress the photocatalytic activity of $TiO_2$ nanoparticles. Organic-inorganic hybrid coating solutions were prepared by reacting the $TiO_2-SnO_2$ nanoparticles with 3-glycidoxypropyl trimethoxysilane (GPTMS) by the sol-gel method. The hard coating films with high refractive index were obtained by curing thermally at $120^{\circ}C$ after spin-coating the coating solutions on the polycarbonate (PC) sheets. The coating films from $TiO_2-SnO_2$ nanoparticles showed an improved pencil hardness of 3H compared to 2H of the coating films from $TiO_2$ nanoparticles. Besides, the refractive index of the coating films from $TiO_2-SnO_2$ nanoparticles enhanced from 1.543 to 1.623 at 633 nm as the Sn/Ti molar ratio increased from 0 to 0.5.

• Journal of Aquaculture
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• v.5 no.2
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• pp.143-155
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• 1992

Effects of vitamin E, C and/or glycyrrhizin in the artificially oxidized feed on the growth and on the resistance aganist Edwardsiella tarda infection to Nile tilapia, Oreochromis niloticus, were examined. The thiobarbitric acid (TBA) values of the oxidized feed were $80\~88$ mg/kg. The fingerling fish were fed the oxidized feed with or without the mixture of vitamin E (50 mg), C (60 mg) and/or glycyrrhizin ($25\~200$ mg) per 100 g of the feed for 7 weeks. The fish fed the oxidized feed with vitamin E, C and/or glycyrrhizin showed better growth than the fish fed the oxidized feed only. But growth rates among the fish fed different amount of vitamins or glycyrrhizin mixed feed were not different. Glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) levels in the serum increased only in the fish which were fed oxidized feed without vitamin E, C and/or glycyrrhizin. With the fish artificially infected with E. tarda: they showed low survival rate when fed oxidized feed and oxidized feed plus 25 mg glycyrrhizin per 100 g feed. The fish fed oxidized feed plus vitiamin E, C and/or glycyrrhizin ($50\~200$ mg/100 g), showed higher survival. These results show that the supplementation of oxidized lipids depress the growth and liver activity, while the addition of vitamin E, C and/or glycyrrhizin in the diet accelerated the growth, liver activity, and the resistance to E. tarda infection.

• Journal of Mushroom
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• v.3 no.3
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• pp.95-99
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• 2005

Carbon dioxide($CO_2$) promotes development of primordia and depress differentiation of sporophore and gill containing basidia, have an effect on quality. This experiments were conducted to elucidate optimal level of $CO_2$ for king oyster mushroom(Pleurotus eryngii). King oyster mushroom was cultivated under 1,600, 2,400, and 3,200ppm $CO_2$. Harvest ratio in normal plot were 98.6, 99.3, and 93.8% at 1,600, 2,400, 3,200ppm, respectively, so 2,400ppm is optimal. The yield per bottle was 102.5g at 2,400ppm, better than 99.7g at 1,600ppm, The $CO_2$ concentration of 2,400ppm was also the best condition for quality, 6.1 at 2,400ppm was 115% of 1,600ppm's. In thinning treatment plot, quality at 2,400ppm was 9.5 better than 1,600ppm whose quality was 9.4. The yields per bottle were 90.7, 98.2, 77.3g at 1,600, 2,400, 3,200ppm respectively. These results show that 2,400ppm was optimal $CO_2$ concentration for quantity of King Oyster mushroom as well as quality.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.1
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• pp.38-46
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• 2005

This study was carried out to quantify the rates of anaerobic mineralization and sulfate reduction, and to discuss the potential effects of benthic fauna on sulfate reduction in total anaerobic carbon respiration in Ganghwa intertidal flat in Korea. Anaerobic carbon mineralization rates ranged from 26 to 85 mmol $C\;m^{-2}\;d^{-1}$, which accounted for approximately 46 tons of daily organic matter mineralization in the intertidal flat of southern part of the Ganghwa Island (approximately $90\;km^2$). Sulfate reduction ranged from 22.6 to 533.4 nmol $cm^{-3}\;d^{-1}$, and were responsible for $31{\sim}129%$ of total anaerobic carbon oxidation, which indicated that sulfate reduction was a dominant pathway for anaerobic carbon oxidation in the study area. On the other hand, the partitioning of sulfate reduction in anaerobic carbon mineralization in October decreased, whereas concentrations of Fe(II) in the pore water increased. The results implied that the re-oxidation of Fe(II) in the sediments is stimulated by macrobenthic activity, leading to an increased supply of reactive Fe(II), and thereby increasing Fe(III) reduction to depress sulfate reduction during carbon oxidation.

• Korean Journal of Food Science and Technology
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• v.17 no.6
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• pp.500-505
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• 1985

A method to store concentrated milk in the liquid state at $-15^{\circ}C$ was developed, and quality changes during storage of milk were evaluated. Combined cryoprotectants (CCP) suitable for storing concentrated milk in the liquid state at $-15^{\circ}C$ were consisted of 17.74% sucrose, 8.87% glucose, 8.87% fructose, 2% glycerol, 0.25% sodium hexametaphosphate, 0.25% NaCl and 0.02% ascorbic acid. The amount of CCP to be added to concentrated milk to depress freezing point to $-15^{\circ}C$ was 38% by weight. Gelation due to protein denaturation was the most serious quality change during storage, which adversely affected appearance and utilization of the stored product. Gelation was observed after 3 weeks storage in the control, but it was not in milk with CCP throughout 18 weeks storage. Amount of protein precipitated increased in the control during storage, whereas there was no protein precipitated in milk with CCP. Surface color and peroxide value of the control and treatment did not change significantly during storage, and there were no marked differences between the control and treatment. These results indicated that quality of concentrated milk could be preserved, without gelation, by storing milk with CCP in the -liquid state at the frozen storage temperature. Besides, energy required for freezing preservation of milk could be significantly reduced by elimination of phase changes for freezing and thawing, and the stored product could be continuously processed for the final products without long waiting time for thawing.

• YAKHAK HOEJI
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• v.34 no.3
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• pp.180-191
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• 1990

A comparison was made of the effects of selective ${\alpha_1}-adrenoceptor$ agonist phenylephrine and selective ${\alpha_2}-adrenoceptor$ agonist clonidine on endothelium-containing and endothelium-denuded rings of the rat aorta. In the case of phenylephrine, removal of endothelium increased sensitivity 2.5 fold at $EC_{50}$ level and maximum contractive response 1.4 fold. In the case of clonidine, which gave only 15% of maximum contractive response given to phenylephrine on endothelium-containing rings, removal of the endothelium increased sensitivity 5.6 fold at $EC_{50}$ level and maximum contractive response 5 fold, which was about 55% of that given by phenylephrine. In endothelium-denuded ring, phenylephrine-induced contraction tended to be more increased in tonic contraction than in phasic contraction as compared to that in endothelium-containing ring, while clonidine-induced contraction was monophasic and was increased only in tonic contraction. In the calcium-free solution or in the presence, of verapamil, contraction stimulated by clonidine was almost abolished while that stimulated by phenylephrine produced only phasic contraction. The depression of sensitivity to these agonists in rings with endothelium appeared to be due to the vasodepressor action of endothelium derived relaxing factor (EDRF), because hemoglobin, a specific blocking agent of EDRF, abolished this depression. It is unlikely that the endothelium-dependent relaxation was due to stimulation of release of EDRF, because clonidine did not produce endothelium-dependent relaxation in 5-hydroxytryptamine-precontracted ring even when its contractile action was blocked by the ${\alpha_1}-adrenoceptor$ antagonist, prazosin. When the efficacy of phenylephrine was reduced to about the initial efficacy of clonidine by pretreatment with dibenamine, the contraction-response curves for phenylephrine became very similar to the corresponding curves obtained for clonidine before receptor inactivation. In the dibenamine-treated rings, contraction of phenylephrine was abolished in calcium-free solution or in the presence of verapamil like that obtained for clonidine before receptor inactivation. These results suggest that EDRF spontaneously released from endothelium depress contraction more profoundly in a case of an agonist with low efficacy and the phenylephrine-induced contraction was totally dependent on extracellular calcium as was that obtained for clonidine when the efficacy of phenylephrine was reduced to that of clonidine by irreversible inactivation of ${\alpha_1}-adrenoceptor$ with dibenamine.

• Journal of the Korean Chemical Society
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• v.19 no.3
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• pp.186-192
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• 1975

In the course of anthracite briquet combustion, air draft is usually controlled to continue burning of definite amount of briquet in the conventional hollow clay cylinder with air inlet hole open for given time, so that a large amount of CO tends to be produced. Therefore, it is necessary to establish an improved combustion process to depress the yielding rate of CO and for this purpose, we performed a basic experiment in which combustion rate of CO was measured in the mixture of $N_2, O_2 $and CO gas with or without the presence charcoal at the various temperature. The observed results showed that the burning temperature of CO is about 680${\sim}700^{\circ}C$, further burning rate of it was increased with increasing the amount of draft. From these facts, longer combustion time and low CO generation are thus contradictory to each other and it has been long desired to make those two compatible somehow. The purpose of the present investigation lies in designing an effective new briquet stove to meet the above requirements. The essential feature of the new briquet stove consisted in the use of two hollow iron cylinders with different inside diameter. A cylindrical air jacket thus formed served as a path through which small amount of secondary air run from the bottom of the stove to the upper vent holes. Heat exchange occurred between the upgoing secondary air and the burning briquet, which lowered the combustion temperature of the briquet. The results observed were selfevident as anticipated. It was confirmed that the combustion time was increased tolerably due to the heat loss from the combustion zone and that CO in the flue gas was reoxidized at the upper portion of the stove by the upgoing hot secondary air. By this reoxidation reaction the concentration of CO in the flue gas was found to be about 1/20 of that in case the conventional clay cylinder was used as briquet jacket.

• The Korean Journal of Zoology
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• v.32 no.1
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• pp.55-73
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• 1989

The effect of tryptophan or serotonin on the early stage of chick brain development has been morphologically investigated using an electron microscope. The electron micrographs of neural plate cells of 1-day chick embryo treated with tryptophan or serotonin showed irregularity, evagination and disruption of nuclear membrane and nuclear chromatin condenstation, nucleolar margination and segregation. Hypertrophy of stalks, vesicles and vaculoes were seen and dilated and disrupted rough endoplasmic reticulum and underdeveloped neurotubules were also observed. In mesenchyme cells of tryptophan or serotonin administered 18 hr embryo, irregular nuclear membrane, swollen mitochondria, dilated rough endoplasmic reticulum and very large yolk granules were observed. Furthermore, DNA, RNA and protein contents of the embryos treated with typtophan or serotonin were considerably lower than those of control group. The amount of tubulin of the experimental groups was also greatly lower than that of control, suggesting that the impairment of microtubule formation occurred. Tryptophan or serotonin administration might depress the biosynthesis, of nucleic acid and protein including some enzymes tested. It seems that the serotonin formed from exogeneous tryptophan might inhibit the degradation of yolk granule by feedback regulation mechanism so as to impair microtububle and microvilli formation followed by a malformation of chick embryos.

• Korean Journal of Food Science and Technology
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• v.42 no.6
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• pp.743-749
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• 2010

The present study was conducted to evaluate the effects of resistant starches (RS2, RS3) on weight change and defecation states in rats with constipation induced by loperamide. Sixty male Sprague-Dawley rats were divided into the following six groups: normal control-5% cellulose (NC), constipated-5% cellulose (CC), constipated-5% pectin (CP), constipated-5% RS2 (CR2), constipated-8% RS2 (CR2-H) and constipated-5% RS3 (CR3). The animals were fed AIN76-based experimental diets for 5 weeks. Supplementation of RS2 and RS3 resulted in significantly lower feed efficiency ratios and body weight gain as compared to cellulose supplemented group. Large intestine length was significantly longer in the resistant starch and cellulose groups than in the pectin group. Relative fecal weight to feed intake was significantly higher in the RS3 resistant starch group than in the pectin group, and the appearance of feces was similar to that of the cellulose group. Supplementation of RS3 or cellulose significantly shortened gastrointestinal transit time in the constipated rats as compared to pectin. The results of the present study demonstrated that resistant starch supplementation, especially RS3, may help in depress body weight gain and alleviate constipation through an increase of fecal weight and shortening gastrointestinal transit time in constipated animals.

• Korean Journal of Poultry Science
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• v.25 no.4
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• pp.185-193
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• 1998

This experiment was conducted to investigate the effect of dietary supplemental Astragalus membranaceus on performance and meat quality of broiler chicks for 5 weeks. Basal diets based on corn and soybean meal contained 21％ crude protein for the first three weeks and 19％ for the rest of two weeks. Four levels of dietary Astragalus membranaceus(0, 0.25, 0.50, 1.00％) were fed in a one way design. There were four replicates of 50 chicks per treatment. Weight gain, feed intake, feed efficiency, blood component, breast meat lipid and protein were measured at the end of experiment. No increased growth rate was observed in chicks fed the basal diet supplemented with Astragalus membranaceus. Chicks fed the diet containing 0.5 and 1.00％ Astragalus membranaceus tended to depress the growth rate. Feed intake of 0.25％ Astragalus membranaceus treatment was significantly lower than control group(P<0.05), Dietary supplemental Astragalus membranaceus improved the feed efficiency compared to the control group, but was not significantly different between them. However, Astragalus membranaceus treatment exhibited decreased serum cholesterol and AST compared to those of control group, but was not significantly different between supplemental groups. Serum hematocrit, triglyceride, phosphate and BUN decreased at 0.25％ Asparagus membranaceous supplementation. Growth hormone and IGF-1 (ng/ml) of chicks fed more than 0.50％ Astragalus membranaceus significantly decreased compared to those of control(P<0.05). The total lipid and protein content of chicks fed 0.25 and 0.50％ Astragalus membranaceus tended to increase, but did not show consistency at more than 0.50％ supplement. The results of this experiment indicated that optimum dietary Astragalus membranaceus level to improve the performance and meat quality of broiler chicks may be less than 0.25％.